Currently, inspection for damage to aircraft composite structures due to fatigue or impacts must be performed on a fixed schedule. These inspections are done to assess the integrity of the structure in question. Each inspection is time-consuming and is costly, not only in terms of time and skill needed to perform a thorough job, but also in terms of lost revenue from the aircraft being out of service. An automated onboard system for detecting and characterizing damage can eliminate this cost, except when significant damage has actually occurred. In addition, because the damage has been located and/or characterized (e.g., determination of damage size, depth, etc.), repairs can be performed more quickly by using the appropriate repair kits.
Transducers are typically large, expensive and require individual wiring. In certain applications, the additional weight of the wiring and/or the transducers may be prohibitive, especially for airborne craft. Conventional wiring is also very heavy and requires a large amount of manual labor to install. In addition, the cost of a large number of transducers applied over a large area may be prohibitive. Another drawback to the use of large, known transducers is that the signal-to-noise ratio for the long paths between the actuators and sensor is much lower than that of shorter paths. Long paths make it difficult to localize and determine the shape of a damage site.
What is needed is a lightweight scalable system and method that allows the assessment of the integrity of a structural body, including large structural bodies, in real-time or near real-time wherein the location and the characteristics of any damage present can be determined.